Cascade long-period pohotonic crystal fiber grating temperature sensor

Abstract

The invention relates to a cascade long-period pohotonic crystal fiber grating temperature sensor. A photonic crystal fiber is provided with a cladding consisting of periodically arrayed air holes; the cladding and a fiber core of the fiber are made of SiO2; a long-period grating with a certain period is written onto the fiber; the air holes of the cladding are filled with thermosensitive substances sensitive to temperature; the refractive indexes of the thermosensitive substances are less than the refractive index of the fiber core; and the total internal reflection photonic crystal fiber is formed. The effective refractive index of a coupled mode of the grating can be changed by controlling the temperatures of the thermosensitive substances, so that the resonant wavelength of a transmission spectrum of the grating is changed, the temperature variation is shown as spectral shift, and the wavelength-tunable temperature sensor is realized. As the bandwidth of the transmission spectrum of the single long-period grating is greater, the temperature sensitivity and the measurement precision of the transmission spectrum of the long-period grating are limited, and the sensor is transformed into a cascade long-period grating structure. The sensor achieves the tunable wavelength, the sensitivity is improved, and the sensor has a very large application prospect in the transduction field.

Description

technical field [0001] The invention relates to a photonic crystal optical fiber engraved with cascaded long-period gratings and filled with liquid ethanol in the cladding air holes, in particular to a cascaded long-period photonic crystal fiber grating temperature sensor with adjustable resonant wavelength and temperature. Background technique [0002] Long-period fiber grating refers to the introduction of periodic changes in the refractive index in the core of the fiber, and the period is on the same order of magnitude as the infrared wave, usually hundreds of microns. Fiber Bragg grating sensor obtains sensing information by tuning the resonant wavelength. It has the advantages of anti-electromagnetic interference, anti-corrosion, electrical insulation, high sensitivity and low cost, and good compatibility with ordinary optical fibers. It is suitable for precise and accurate measurement. Therefore, making high-sensitivity fiber grating sensors is an important direction f...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to solve the problem that the detection band of the photonic crystal fiber sensor can no longer be changed after the fabrication of the previous photonic crystal fiber sensor, and provide a cascade that can flexibly control its sensing band only by selecting the appropriate grating period and fiber coupling mode Long-period photonic crystal fiber grating temperature sensor, and the measurement accuracy and sensitivity of the sensor are improved by cascading gratings

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